1. The sheet metal cabinet is not allowed to tilt or partially bend or distort. The perpendicality between the frame column and the base is less than 1.5mm. During testing, the upper surface of the base is used as the benchmark, and the inner edge of the upper end of the column is used as the measuring point.
2. The parallelism between the top frame and the base is less than 1mm. The detection points are the upper surface of the base and the lower surface of the top frame, which serve as a reference to each other. It can also be detected by measuring the length of the hexagonal diagonal, and the difference should not exceed 2.5mm. If there is a middle partition board, the parallelism between the top frame and the base can be extended to 1.5mm, and the parallelism between the middle partition board and the top frame or base is less than 1mm.
3. The absolute value of the diagonal difference between the upper and lower boxes is less than 1.5mm.
4. The column shall not be distorted, and the parallelism between the two ends of each column connected to the upper and lower shell frame and the adjacent plane of the shell is less than 0.5mm.
5. To support the guide rails of the sub-frame, the working surface formed by the left and right guide rails of the same layer is 1mm parallel to the upper surface of the base, and the gap between the two adjacent panels behind the sub-frame should be installed. The absolute value must not exceed 0.6mm.